Simple script to see how far users scroll on a website

paragraph_counter.js

(function ($) {
    $.waypoints.settings.scrollThrottle = 30;

    try {
	mpmetrics = new MixpanelLib("<api_key>");
    } catch(err) {
	var null_fn = function () {};
	mpmetrics = {
            track: null_fn,
            track_funnel: null_fn,
	    	track_links: null_fn,
            register: null_fn,
            register_once: null_fn,
            register_funnel: null_fn,
            identify: null_fn
	};
    }
	$(".entry p").each(function (i, el) {
		$(el).waypoint(function (event, direction) {
			if (direction === "down") {
				mpmetrics.track("Paragraph "+i, {url: window.location.href,
												 index: i});
			}
		}, {offset: 'bottom-in-view'});
	});
	

})(jQuery);